a school photocopier has a 95% chance of working on any particular day. Draw a tree diagram showing the possibiltiies for the working or otherwise of the photocopier over 2 consecutive days. Hence, determine the likelihood that it will be working on at least one of these days.
Here is current diagram:
first day& second day
& & work(0.95) / work(0.95)& & & / \ & /& & no work(0.05) / \& work(0.95) & \& / & no work(0.05) & \ & no work(0.05)
So, the probability that a school photocopier will be working on at least one of two consecutive days is P = 0.95*0.95 = 0.95² = 0,9025.